"""Schmaler Ollama-HTTP-Client (Chat + Embeddings).

Keine Tools, kein Browsing, keine Web-Hooks — der Agent hat architektonisch
keinen Weg aus der Wissensbasis hinaus (Grounding-Regel 1).
"""
from __future__ import annotations

from typing import Any

import httpx


class OllamaError(RuntimeError):
    pass


class OllamaClient:
    def __init__(self, base_url: str, embed_timeout_s: float = 240.0,
                 chat_timeout_s: float = 300.0):
        self.base_url = base_url.rstrip("/")
        self.embed_timeout_s = embed_timeout_s
        self.chat_timeout_s = chat_timeout_s
        # Per-Request-Timeouts mit kurzem Connect-Budget — ein unerreichbarer
        # Server muss in Sekunden, nicht Minuten scheitern.
        self.embed_timeout = httpx.Timeout(embed_timeout_s, connect=10.0)
        self.chat_timeout = httpx.Timeout(chat_timeout_s, connect=10.0)
        self._client = httpx.Client(timeout=self.chat_timeout)

    def close(self) -> None:
        self._client.close()

    # -- Infrastruktur ------------------------------------------------------

    def is_up(self) -> bool:
        try:
            r = self._client.get(f"{self.base_url}/api/tags", timeout=5.0)
            return r.status_code == 200
        except httpx.HTTPError:
            return False

    def list_models(self) -> list[str]:
        r = self._client.get(f"{self.base_url}/api/tags")
        r.raise_for_status()
        return [m.get("model", "") for m in r.json().get("models", [])]

    # -- Embeddings ---------------------------------------------------------

    def embed(self, model: str, texts: list[str]) -> list[list[float]]:
        """Batch-Embeddings via /api/embed; Fallback auf Legacy /api/embeddings."""
        r = self._client.post(
            f"{self.base_url}/api/embed",
            json={"model": model, "input": texts},
            timeout=self.embed_timeout,
        )
        if r.status_code == 404:
            out: list[list[float]] = []
            for t in texts:
                rr = self._client.post(
                    f"{self.base_url}/api/embeddings",
                    json={"model": model, "prompt": t},
                    timeout=self.embed_timeout,
                )
                rr.raise_for_status()
                emb = rr.json().get("embedding")
                if not emb:
                    raise OllamaError("legacy /api/embeddings returned no embedding")
                out.append(emb)
            return out
        r.raise_for_status()
        emb = r.json().get("embeddings")
        if not isinstance(emb, list) or len(emb) != len(texts):
            raise OllamaError(f"unexpected /api/embed response for {len(texts)} inputs")
        return emb

    # -- Chat ---------------------------------------------------------------

    def chat(self, model: str, messages: list[dict],
             temperature: float = 0.1, num_ctx: int = 16384,
             num_predict: int = 1024, think: bool = False) -> str:
        """POST /api/chat, stream=False; `think`-Flag mit 404/400-Fallback."""
        body: dict[str, Any] = {
            "model": model,
            "messages": messages,
            "stream": False,
            "options": {
                "temperature": temperature,
                "num_ctx": num_ctx,
                "num_predict": num_predict,
            },
        }
        if think is not None:
            body["think"] = bool(think)
        r = self._client.post(
            f"{self.base_url}/api/chat", json=body, timeout=self.chat_timeout
        )
        if r.status_code in (400, 404) and "think" in body:
            # Ältere Ollama-Versionen kennen das think-Flag nicht -> Retry ohne.
            body.pop("think")
            r = self._client.post(
                f"{self.base_url}/api/chat", json=body, timeout=self.chat_timeout
            )
        r.raise_for_status()
        data = r.json()
        msg = data.get("message") or {}
        content = msg.get("content") or ""
        if not content.strip():
            raise OllamaError(f"empty response from {model} (keys: {list(data.keys())})")
        return content